Gas passes



Aug. 13, 1968v R. BAGLEY ETAL 3,396,707

GAS PASSES Filed Aug. 25, 1966 4 Sheets-Sheet 1 Aug. 13, 1968 R. BAGLEY ETAL 3,396,707;

GAS PASSES 4 Sheets-Sheet 2 Filed Aug. 25, 1966 lllil Jmum i i 4 0 it Aug. 13, 1968 R. BAGLEY ETAL GAS PASSES 4 Sheets-Sheet 5 Filed Aug. 25, 1966 g- 13, 1.968 R. BAGLEY ETAL 3,396,707

GAS PASSES Filed Aug. 25, 1966 4 Sheets-Sheet 4 United States Patent 3,396,707 GAS PASSES Roy Bagley and Richard H. Evans, London, England, assignors to Babcock & Wilcox, Limited, London, England, a corporation of Great Britain Filed Aug. 25, 1966, Ser. No. 575,157 Claims priority, application Great Britain, Aug. 27, 1965, 37,046/ 65 3 Claims. (Cl. 122-510) ABSTRACT OF THE DISCLOSURE A gas-pass having tubes in the walls thereof where the tubes discharge fluid into headers positioned in the upper portion of the gas-pass walls. The headers in opposite walls are provided with conduits extending across the top of the gas-pass which discharge fluid from the opposite headers into a collector located parallel to and intermediate the headers in opposite walls. The conduits from opposite headers are tied together to resist forces urging the opposite headers apart.

This invention relates to gas passes and enables portions of the fluid flow path to be utilized as structural components of the gas pass.

According to the present invention, there is provided a gas pass having at the upper ends of opposite walls collector means into which tubes lining the walls discharge, conduits extending towards each other from the collector means across the top of the gas pass, and means tying the conduits together to resist forces urging apart the collector means between which they extend.

According to the present invention, there is also provided a gas pass having at the upper ends of each of two opposite walls a plurality of headers into each of which a group of wall lining tubes, connected for parallel flow of working fluid, discharge, each header being connected for fluid flow to a conduit extending at the top of the gas pass towards a header at the opposite side of the gas pass, and the conduits that extend towards each other from opposite headers are connected together to resist forces urging the headers apart.

By way of example, an embodiment of the invention will now be described with reference to the accompanying drawings in which FIGURE 1 shows somewhat diagrammatically a vertical section through a once-through, forced-flow vapour generator and superheater;

FIGURES 2a and 2b form a diagram showing the walls of the upright furnace chamber of this generator developed into a single plane; and

FIGURE 3 is a perspective diagram illustrating certain details of the side walls and the top of the upright gas pass of the generator.

The once-through, forced-flow vapour generator and superheating unit illustrated in FIGURES 1 and 2 includes a furnace chamber 1 forming the lower end of an upright gas pass 2 and fired by thirty circular burners, such as 3, in each of the front and rear walls, 4 and 5, of the gas pass 2. The lower end of the gas pass 2 ends in a hopper bottom 6, the front and rear walls 4a and 5a of which are convergent whilst the side walls are parallel.

A lateral gas pass 7 containing reheater tubes 7a extends from the upper end of the rear wall 5 and discharges combustion gases into the downpass 9 containing economiser tubes 9a. The walls of the gas pass 2 are lined in a manner that is described in our co-pending application S.N. 574,974, up to the level of the inlet to the lateral gas pass 7 by tubes that extend generally lat- 3,396,707 Patented Aug. 13, 1968 erally but rise generally continuously. At the level of the inlet to the lateral gas pass 7 each of these tubes is connected to a vertical tube, the vertical tubes in the front and side walls being arranged side-by-side in groups 10. Each group 10 of tubes is provided with a header 14 and each header 14 connected by means of a conduit 14A to a collector or receiver 15, extending centrally across the top of the gas pass. The spaces between the groups 10 are filled by further groups 11 of vertical tubes in a manner that is described more fully in our co-pending application S.N. 574,974, the tubes of the groups 11 being supplied with fluid from the collector 15.

The front and side walls are suspended by means including vertical tension members 12 lying outside the boundary walls of the gas pass 2, being connected at their lower ends to the walls and supported by springs 13 at their upper ends. Each tension member 12 associated with the front and side walls lies alongside one of the groups 10 of vertical tubes. Similar tension members are associated with the rear wall in a manner described more fully in our co-pending application S.N. 574,974.

The support straps extend alongside the tube lining internally of lagging and are supported by a system of buckstays outside the lagging. The system includes horizontal buckstays 17 connected to the transversely extending tubes of the tube lying so that the tubes themselves withstand the pressures urging opposed buckstays apart.

Platens of U-shaped superheater tubes 15 are suspended in the upper end of the pass, depending from beams :16 connected to certain of the springs 13.

At their upper ends, each of the tube lengths included in a group 10 discharges into a corresponding header 14. A collector, or receiver, 15 extends from front to back across the middle of the top of the gas pass 2 and each of the headers 14 at the upper ends of the side walls is connected to the collector 15 by means of a conduit 14A extending horizontally for the most part but cranked upwardly at 1413 for connection to the collector 15. As will be seen from FIGURE 3, each conduit 14A extending towards the collector 15 from one side of the gas pass is aligned with a conduit 14A extending towards the collector 15 from the other side of the gas pass.

Aligned conduits 14A are tied together by means of ties 19 in the regions 14B in which they are cranked. In one form, each tie 19 is a pair of metal strips each welded at one end to one conduit 14A and at the other end to an aligned conduit 14A. In another form, each tie is in the form of a pair of metal strips clamped by means of bolts to aligned conduits 14A.

Thus, the conduits 14A that extend along the top of the pass and are tied together to form a brace resisting the effects of gas pressure inside the gas pass 2 tending to urge the side walls apart. The walls of the gas pass will, of course, be reinforced by buckstays extending laterally along them.

As is shown in our co-pending application S.N. 574,974, the headers of the tubes in the groups 10 may also be connected to the collector 15 and fluid from the collector 15 distributed through ducts 15A to the inlet headers of the tubes in groups 11.

In modifications of what has been described, not all the aligned pairs of conduits 14A need be connected together. Moreover, the connections may be replaced or augmented by connections between conduits extending towards each other from the headers into which the tubes of the groups 11 discharge.

What is claimed is:

1. A gas-pass defined by walls having tubes therein, headers positioned in the upper portion of opposite walls of said gas-pass, means for passing fluid through the tubes in said opposite walls into said headers, conduits extending toward each other from each of said headers across the top of said gas-pass, a collector positioned parallel to and between the opposite wall headers of said gaspass to receive the fluid from said conduits, each of said conduits having an end portion bent substantially perpendicular to the remaining portion of the conduit and opening into said collector and means tying the bent end portions of said conduits together to resist forces urging apart the headers in said opposite walls.

-2. A gas-pass according to claim 1 wherein a plurality of headers are positioned in the upper portion of each of said opposite walls, at least one conduit extends across the top of said gas-pass from each header toward a cor- 4 a .1 and the bent end portion of corresponding conduits opening to said collector are in side-by-side relationship.

3. A gas-pass as claimed in claim 2 in which the tying means is efiected by members welded between the upper 5 end bent portions of the corresponding conduits.

10 3,315,647 4/1967 Triggs 122-478 FOREIGN PATENTS 1,334,730 7/1963 France.

responding conduit from a header in the opposite wall, 15 KENNETH SPRAGUE, primary Examiner 

